Method of forming optical prisms



June 27,1944. Q KENDE r- T AL 2,352,551

METHOD OF FORMING OPTICAL PRISMS Filed March 2, 1942 7 Sheets-Sheet 1 v/ .fl e

June 27,1944. KENDE ETAL f O 2,352,551

METHOD OF FORMING OPTICAL PRISMS AFTER Zw off/'m T/o/v INVENTORS avg ATTORNEY AFTh-30 OPERATION f Ta Q7 Brone [amm June 27, 1944. KENDE E-rAL` 2,352,551 Y METHOD OF FORMING OPTICAL PRISMS Filed Ilarch 2, 1942 7 Sheets-Sheetv 3 A l 7c 7d I O A BOT/1 ENDS FINISHED WER [$1 UPRMUN fren Zuoorenanon A l nnen 3d artnr/ou ATTORNEY 'INVENTORS June 27,1944- G. KENDE Erm. 2,352,551'

' muon oF FoRmm-f omen. rnrsms v Filed Maren 2. 1 942 7 sheets-.sheet 4'l ATTORNEY June 27, Q vKENDE; ETAL l METHOD OF FORMING OPTICAL PRISMS Filed March 2. 1942 v 'r sheets-sheet 5 iNVENroR-Q ZW/M BY @ATTORNEV June 27, 1944. G, KENDE ITAL METHOD oF pomme OPTICAL PRIsMs Filed' Marche, 1942 l sheets-sheet 6 MFP/2J JNVENTogS a U n A ATTORNEY .m R E P NO o m3 .mm Q a m/m F 4A a H Arrzn lsr OPERATION aPMnoN BeFons lsv June 27', 1944.

v Filed` March 2, 1942 7 sheets-sheet 7 f 'Gesu-4g BY I ATTORNEY which such optical components.

Patented June 21,1944 i .UNITED STATES PATENT. oFl-rcE ME'rnon or'roamNG OPTICAL raisins George Rende, Dobbs Ferry, and Eli Elison and Sten Johanson, New-York, N. Y., asslgnors to Corporation, New- York, of 'New York Application Maren 2,1942, serial Nn. 422,944 i 12 claims. (c1. 51-118) Universal Camera N. I., a corporation- This invention relates generally to the processing of frangible material and is more particularly directed to a method and apparatus for grinding molded or otherwise formed glass units in the specific contours asA also insure the maximum amount of service that may be obtainable from a grinding element, before it is necessary to replace it, thereby addingto the economic advantages of our invention.

Another important object of our invention is the provision of a mechanism or apparatus, possessing the heretofore recited advantageous features. which will admit of further accelerated production by rendering it 4possible to perform certain similar operationssimultaneously, as, for example, reducing the cross-sectional area of a unit, by removing material from the opposite sides thereof by the con'joint functioning. of associated grinding media or elements.`

Other objects and advantages flowing from the practicing of our invention will become evident as the description proceeds and we would have it may be essential to the purposes to-which the completed units are to be applied. Obviously, these hand grinding methods not only limit the rate of production, but result in an appreciable waste or spoilage of material, because of improper manipulation of handling of the units during some stage of the grinding process, all of which, of course, contribute to the high manufacturing -costs and retard production of apparatus of umts are to become essential Therefore, the primary object of this invention is to provide a method of overcoming the disadvantages inherentto the present hand grinding operations, referred to, in the production of optical devices, as prismsA and the like, by utilizing automatically functioning mechanisms for doing the work now performed by hand, thereby not only eliminating the drawbacks, economically and otherwise, of slow production, but insuring unl- 'form accuracy in .dimensioning and profiling the units, for their subsequent completion by polishing, which is not attainable with existing methods, waste or spoilage by breakage pr inexact being thus reduced to an abslute n iinimum. t

More specifically, it is the object of this invention to provide a simple and ei'licient mechanism for progressively processing, as by. grinding, a series of units by the automatic functioning of the mechanism, the dmensioning of the units and the profiling or contour-forming operations being accomplished in successive steps or stages, in the practicing of my method.

It is also an object of our invention to provide an apparatus or mechanism, as aforesaid, which will possess a range of adjustability, whereby units of different sizes may be processed and which clearly understood that we reserve unto ourselves all rights to the full range' of equivalents of the steps of our method and the apparatus whereby they may be carried into eiect, within the scope of the appended claims.

Briey stated, our invention contemplates an `apparatus or mechanism for practicing our method of processing optical devices in an expeditious and emcient manner, which, preferably, includes three steps, the reduction of the rough prismatic casting to the requisitecross-sectional Adimensions,'by simultaneously subjecting both sides thereof to the action of mated grinding elements, being followed by grinding the ends of the unit in successive similar operations, to impart the desired contour thereto,V arcuate or otherwise, as may be necessary for the purposes to which thecompleted unit is to be applied, after which the -roof or apex is ground to obtain the required `height and prole, the sequence of these steps, ofcourse, being subject to change to meet operational and other requirements.

In the operation of the mechanism or apparatus, for the performance of each of the aforesaid' several steps, a revoluble work carrier to which the unit may be manually applied, to be sequentially automatically locked in position thereon during an initial period of its rotative movement, successively exposes the units clamped thereto to the action of a series of grinding elements successively etlv'ective on each unit, in a continuing movement of the carrier, the units, as they pro- A gress from the finalA grinding operation of the step of the method then being performed, being automatically released for removal from the revolving carrier. 'l'he mechanism may. be operated eontinuousLv at a predeterminedspeed, over long periods of time and during s uch operation,

l step,

lineI-I of- Figure 4.

optical units that are to, besubjected to a specific grinding step may be entered. upon a carrier in replacement of those which are removed therefrom, following the completion of such grinding with the obvious elimination of those production lags which must inevitably result from machine stoppages and the locating of the work therein.

In other words, by utilizing my method and apparatus or mechanism, functioning in the manner described, for rendering our invention effective, so-called setting-yup 6r preparato'n of the work in the apparatus is wholly unnecessary, the units being readily locatabie upon the carrier in defined positions, the subsequent progressive' 'work-clamping and grinding operations and the release of the work on the completion of the final grinding 'stage being entireiyautomatic. Manifestly, not only is continuity :of production possible, but the economic advantages thereof inay be attained with the use of unskilled labor, the

mechanism being so designed that abattery of machines may be eniciently supervised and the work applied to and removedfrom the individual mechanisms thereof by a single operator.

In the accompanying drawings',.we have shown a preferred and practical embodiment of. apparatus for carrying our invention into effec..

Figure 1l is a transverse sectional view, showing the cooperating or paired grinding wheels for performing 'theiirst and third operations in the progression of thework through the roof grinding mechanism assembly of- Figure 9.

Figure 1 2 is an assembled view, taken from one end of the prism, showing the dimensional and contour changes `that are produced in the operation of the roof grinding mechanism, and

Figure 13 is a vertical transverse sectional view, showing a representative grinding mechanism assembly; and specifically illustrates the roof grinding mechanism assembl as in Figure 10, and the means employed for relatively adjusting the intermediate grinding `element and the workcarrier in a vertical plane, to vary the amount of material that is cut away in t e second operation of the roof grinding step an likewise compensate for wear of the grinding element.

In' the following detailed description of the construction and operation `,of the apparatus shown, I shall refer to three separate arid distinct steps, which will be described in the order-in However, the apparatus'may take other forms,

with such structural variations or substitutions as may be essential to particular applications or uses, in the practicing of our method, without departing from the spirit and scope of our invention.

In the drawings:

Figure 1 is a view in. elevation (taken from the left of Figure 2) partly in section, of the revoluble work-carrier and associated grinding elements, that is utilizedto reduce the cross-sectional dimensionsof a prism, by simultaneously .removing material from each of the opposite sides thereof.

Figure 2 is a vertical cross-section on the line 2-2 of Figure 1. s

Figure 3 is an assembled diagrammatic view, showing a prismatic casting and the degree of reduction that is produced in its transverse area, in the functioning of the grinding elements'of the preceding figures.

Figure 4' is a view similar to Figure 1, of the form of work-carrier and cooperating grinding media, that is employed in the performance of the two corresponding phases of the second step of our method, whereby the ends of the prism i are ground to the desired contour.

which they are preferably performed, in the functioning of ,the apparatus. The first of these, is that in which'both sides of a prism are simultaneously ground or reduced. The second is an end processing step, involving two similar phases, preferably successively performed, in winch the ends of a prism are given the required identical contour, and the third and final step is the prism roof-formingoperation. If desired, or found necessary, the sequence of the steps may be varied, as heretofore pointed out; also, the contours produced may differ from those shown, as a result of profiling steps, in the production of prisms and other optical devices, it being-'understood that the term prism is used in a generic sense, to include all such optical devices as may be produced in accordance with my invention.

Referring now to the drawings in' detail, in which like ycharacters of reference are employed to designate similar. parts in the several views, and more particularly to the mechanism for simultaneously reducing both side faces of a prism, as shown in Figures 1 and 2, a work-carrier in the form' of a disc-wheel I5, embodying ahub ,Figure 'I is a view corresponding to Figure 3,

illustrating the changes which are .produced in the contour of one end, in the progression of the prism through the three grinding zones of the assembly of Figures 4,5and6;

Flguresisaviewofaprism,

` both ends or which have been subjected to the end grinding-operation.-

AFigure91saviewinelevatiornparizlyinsection of the rotatable work-carrier and grinding ele-A ment assembly, which we employ in grinding the prism roof or apex,

'Figure 10 is a vertical cron-sectional view on the line I O-Il of the preceding figure.

l the end' side of a work-receiving seat, while .the inner' sur- IG, is keyed to a shaft I1,fas `at Il, for rotation at slow speed, in a counter-clockwise direction, as and for the purposes which will behereinafter more fully described. l The inner face of the wheel .Ii is providedwith ya series of preferably integral laterally projecting bosses, of the configuration shown in Figure 1, equidistantly `spaced along its periphery" which is recessed or undercut between adjacent bosses, as at 2l, whereby said bosses, in coniunc- .tion with the rim or flange 2| cooperate in theformation of a series of work-receiving seats, said -rim or nauge which is offset relatively to' the body of the wheel, being fixed to the periphery thereof, between the aforesaid recessed portions 2l, as by the screws 2lb. Each boss embodies an obliquely disposed surface Isa complemental to face of a-prism, which constitutes one.V

face of the rim 2l, in the/area of the recesses lijf 4is undercut, as at lla, to'provide a surface coinplemental to a prism base. The width of the cooperating seat`dening surfaces lia and Ila, is -less than the transverse dimensions of the prisms thataretobe,sothatapri sm located in a 'seat for p, with its base-superimposed upon the surface 2id, will project outwardly of the seat, at both sides thereof, whereby simultaneous reduction of the two side faces of the prism may be plained.

Rockably mounted on a bolt or stud 22, adjacent, each work-forming seat, is a lever 23, bifurcated at one end, for the reception of a cam roller 24, the opposite Aend of said lever terminating in a nose 25, shaped to provide a surface complemental to a part of the end face of a prism, with which it is adapted to engage, in the manner 'hereinafter set forth, the nose, preferably, being enveloped in, or coated with, conforming brous or yieldable material, as indicated at 26. An expansion spring 21, interposed between a seat 28 on said lever, adjacent the cam roller 24, and a lcooperating seat formed on `the contiguous` boss I9, normallyfunctions to urge the nose of said lever toward the opposite surface 19a of such boss,

effected as hereinafter exwhich the clamping elements become ineffective,

4so that they may be removed from their seats,

the slow speed at which the carrier rotates making it possi-ble for the Aoperator to remove the processed prisms and substitute others for grindwithout arresting the movement of the workcarrier.

- sides pass between a fixed the reception of a Vring 32,ixed thereto, as by -screws 33. This ring embodies a cam surface 34, Awhich is adapted to be traversed by the cam rollers 24 of the respective levers, during a part of the cycle of the relative rotative movement of the work-carrier, to progressively actuate the levers 23 Ito one extreme position, in oppositionto their springs 21 and to similarly control the spring-induced movement of said levers in a reverse direction, from such `initial 'extreme position, to a second extreme position. Y

As clearly shown in Figure 1 of the drawings, the cam 34 is laid out in an arc of 180 upon the upper portion of the ring 32,- extending from a point 22E/2*? belowa horizontal line drawn through thecenter of the shaft I1 to a point the same distance above such line on the opposite side, the pitch or curvature of the eiective surface thereof, providing for a progressive movement of the levers in opposition to their springs 21, as the cam rollers successively enter upon and traverse the cam to ride upon an intermediate portion of the surface thereof, indicated at 34a, when they become inactive. The nose portions of the levers in this inactive position, are so disposed within The areas of the recesses, that prisms may be readily inserted in the seats with whichsuch levers are associated, from the side of the work-carrier, each prism being located with its base in registration f with the rim surface 21a and one end abutting As the prisms advance to the'zone in which clamping effort isy initiated thereon 'by-the movement of the levers in response to the expansion of their springs 21, they are accurately centered longitudinally of their seats, as their projecting guide plate and anonpositely spaced cooperating spring means, eiective laterally of the prisms;r to urge them into riding contact with said guide plate. The'semiannular guide plate 35, xed to the frame of the apparatus, inwardly of the work-carrier, as by upon the adjacent ber plug 29. As the workcarrier continues its-rotative movement, in the direction of the arrow.,and'the cam rollers successively leave the portion 34a of the cam surface, the gradually diminishingr pitch of the cam surface permits their springs 21 to gradually expand to cause the nose portion of each lever to Vmake contact withthe juxtaposed end of the prism and exert progressively increasing pressure thereon, to urge it into close association with the opposed plug 23, and into positive engagement with the coacting rim surface 2Ia..the prism being rigidly locked in this nal position in response to the counter pressureof the plug and lever nose 25, effective thereon, as the cam roller leaves the cam surface. Obviously, this cycle may becontinued indefinitely; as the prisms. rmly clamped. within the seats progress through the grinding stages of the operation. as hereinafter described.

and are successively advanced to the positions in the spacers and cooperating screws 36 and 31, also functions as a locator, in limiting the inward movement of the prisms,as they are inserted in their seats from the opposite side of the workcarrier, while the aforesaid spring means are carried by an arcuate platel 38 which is likewise secured to the1 frame ofv theV apparatus by suitable bolts and spacers 4U and 4|', parallel to that' portion of said plate 35 which lies within the aforesaid zone, in laterally spaced relation thereto.

Mounted on the inner face vof the plate 38 are a pair of spring blocks 42 and 43, to which'the springs 44 and- 45, having inclined intermediate portions, are secured, the free ends of said springs being connected by a flexible surface 46, which is adapted to contact with the adjacent side faces of the prisms, as theyv progress thereby, the spring A action permitting the-flexible surface to engage an advancing prism that may -be out of line andV urge it into position, as the prism progresses toward the position -inwhich the clamping action, as heretofore described,-is completed.

Mounted below the .work-carrier are a series of grinding elements, arranged in pairs, each pair, functioning as a unit, being peripherally spaced from the adjacent pair, their axes ofv rotation being located on a curvilinear line, parallel to the orbit of rotation of said work-carrier, the prisms clamped vin said work-carrier successively passing between the spaced sets of grinding elements, indicated at a, b and c, to expose their protruding side portions to the abrading action thereof, for progressively reducing the transverse area 1of theY prisms. Y

As shown in Figure 2, each pair or set of grinding elements includes an inner and outer grinding ring wheel -48'and 49, carrying the grinding` rings 48a and 49a, which are-keyed to a shaft 5G, by a common key, as at; 5|, in the appropriate laterally spaced relation, and locked against a shoulder 50a of the shaft and against longitudinal movement, by the nuts 52 and 53, the shaft 50 being mounted in the frame of the apparatus parallel to the shaft I1, in adjustable bearings and being driven in the manner hereinafter described; While the grinding element mounting as just described. refers to the structure of Figure 2, in deit being apparent that the spacer is positioned upon the shaft 50 in contact with the side'of the inner wheel after which the outer wheel is located on the shaft with its hub abutting upon the adjabifurcatedfto carry a cam bodies a the set o'f-grinding elements a of the rst spindle assembly for the simultaneous reduction of both sides of the prism, as their, progression is'continued, in the amount ,determined by the relative spacing of the grinding elements, and that in succession, the prism will be subjected to the abrading action of the remaining sets of grinding elements b and c, in a like manner, the amount of reduction being in decreasingl amount at each f successive stage, until the progressive reduction operation is completed, the movement of the prisms continuing to that .part in the rotation of the work-carrier, where they maybe removed from their seats and others substituted for the reduction of their side surfaces.

In Figure 3, view 3a shows the approximate cross-sectional dimensions and plan of a molded prism base, in the condition in which it is applied to the work-carrier, while view 3b illustrates the reduction that is effected, with theresulting change in outline, in the first stage of the side-reducing operation, the progressive reduction in the second and third or al stages being shown in viewsA 3c and- 3d respectively. a

-In the mechanism shownin Figures 4 to 6, inclusive, which functions in the reduction and profiling of the ends of a prism, in similar, and

preferably, succeeding steps the' Work-carrier comprisesi a disc-wheel 55, embodying laterally projecting seat-forming bosses 56, equidistantly spaced along the periphery ,of said wheel. Each of these bosses is provided with two work-engaging surfaces, the surface 51 being slightly shorter than the' length of the end face 'of a prism P matable therewith, while the shorter surface 58, disposed at an angle of 90 to the surface 51, at the outer terminus of the latter, is adapted to engage the opposite end face of the prism, in a zone adjacent the prism apex. As will be noted from Figure 4, the bosses 58 are relatively angularly offset, so that the surface 51 of each thereof will be disposed to locate the base of a prism parallel to a radial line through the axis of rotation of the work-carrier', when one end face of such` prism is in registrationwith' said surface, with a portion of its opposite end face abutting upon the surface II, for reasons which will become apparent'.

Rockably mounted on a screw I9, on each'boss l., behind the lever, the inner surface l1 thereof, is a bell-crank $2 of said lever is provided parallel -to one side thereouter and shorter arm with a. surface disposed fof, as'indicated'at, which-embodies a central undercut portion.. formed for' engagement with thebase of a prism engagedl with the aforesaid seat-defining surfaces l1 and 5l, as described. An expansion spring M, interposed between the end of the arm 6l carrying'the cam roller 0l, and a suitable seat formed on the aligned base of the immediately adjacent urge the shorterv arm defining surface l1.

'I'he wheel l5 is keyed which'includes similarlyl` to the cam surface ofFigure 1," the length oftheei'fective surface of the cam'surface 8l being greater however, and

a cam surfacel 69 disposed -end of the arm." of which is boss, normally ftends to" toward the prism seatto a shaft 6,5 and e'm-n hub 61, rotatable within the annulus:

.34 on the ring 32 ferent order.

roller Il, while the 4 2,352,155 1 cent surface of the spacer and the assembly locked itscurvature or pitch differing to an extent to provide for the increased number of clamping elements'and the -progressive actuation of the bell-crank levers to their prism-releasing positions, as their cam rollers 6| enter upon and `traverse the cam surface, to ride upon the inter- 69a thereof, for the initiation ofthe spring-induced movement of the bell-cranks and its com- `pletion, as the cam rollers exit from the cam surface 69.

Also, as in the mechanism sides of the prism. the prisms seated in the cooperating surfaces 51 and 58 of the work-carrier 55, pass between a fixed inner prism guidei-l and a yieldable outer guide 1I, which corressponds structurally and in their mode of functioning, to the counterparts of the side-reducing mechanism, previously. described.

Mounted below the work-carrier 55 are a plurality of grinding elements, which include a single grinding wheel and two sets of paired grinding wheels, the mated wheels of each set functioning as a unit simultaneously to reduce and shape opposite surfaces of a prism end. The single wheel and each pair have their axes of rotation disposed along a curvilinear line, parallel to the orbit of r'otation of the work-carrier, as indicated at d, e and f (similarly to the grinding 4elements a, b and c), with the effective surfaces of the wheel in the path of travel `of the depending or protruding ends of the Aprisms clamped in said work-carrier. These ends are successively subjected to the abrading action of the single grinding wheel, .and, in sequence, to the action of the peripherally spaced sets of paired grinding wheels, for reducing the curved end of the prism to form an intermediate fiat portion, and to progressively convert such at portion and the abutting curved surfaces into a final curve of a dif- As shown in Figure 6' of 'the' drawings, the grinding wheel 12rwhich functions in the first stage of \the operation. is keyed to a shaft 13,'

as at 14, and locked thereon by the usual securing nuts 1l and/5,18. The two sets of wheels functioning in the second and third stages of the operation, correspond in all details of structure and assembly. Therefore, the description of the grinding wheel assembly of Figure 5 is applicable to both sets of paired wheels. c

as will be noted, the-matedwheels 11 and n have oppositeiy curved cutting faces, as indicated at- 11a and 18a, and are keyed to the shaft 19, .as at 80, and locked against relative longitudinal movement, thereon, -by the nuts Il and I2, the wheels being maintained in appropriately spaced relation by the spacer 83, I,The shaft 13 and the shafts of the two sets of mated wheels -are'mounted in adjustable. bearings in the apparatus frame and are-driven similarly to 'the grinding element shafts of the structure of Figures 1 and 2, as will be' hereinafter described. 1

Itwul be manifest, that, as the work-carrierV rotates, the projecting ends'of the prisms clamped :to the seats thereof. wm 'n1-st lcontact withthe grindingwheel 12, which will eect a reduction of the rounded end of the .pi-ism', shown ln-vlew for reducing the 2,352,551 "la of Figure 7, t'o produce a at intermediate portionras at the bottom of view 1b. As the prism progresses to the paired grinding wheels e, it passes between them for the reduction of the at surface, to a degreewhereby its length is decreased, the merging curved surfaces at either side thereof having `a curvature of `greater length imparted'thereto, as shown at the lower part of view 1c, of Isaid Figure '7, while the passage of the prism between the mated grinding wheels f, completes the profiling of the'end of the prism base, to produce a curvature ofthe order shown at the bottom of view 1d. As the nal step in this rst phase of the end-grinding and profiling-operation is completed, the prisms, continue their progression to that point in the 'ro- -tative movement of the work-carrier, at .which theymay be removed from their seats, as heretofore explained. When one end of a prism has been reduced and shaped, the position of the prism may be reversed on its seat, so 'that the other end thereof may be similarly processed,a

plan view of a prism winch has passed through `both phases of the end-reducing and profiling operation being shown in Figure 8. When both ends of a prism have been processed, it is, of

course, removed from the carrier and another substituted, it being obvious that prisms may beremoved from the workcarrier and replaced thereon, in reversed position, while it continues to rotate and the grinding elements Vremain operativerupon those prisms which are successively introduced thereto, as described.

The mechanism for performing the third and o final operation in converting a molded prism into lever toward the fixed work-receiving surface 89.

As in the side-reducing and end processing mechanisms, heretofore described, the wheel 84 embodies a hub 94, keyed to the shaft 85, as at 96, the hub being rotatable within the ring or annulus 91, which includes a. cam surface 98,

'corresponding generally to the cam surfaces 34 and 69, its pitch'or'curvature, however, differing from that of the other camsurfaces in conan optical' prism, for subsequentv polishing, in u which the apex of the molded prism is reduced andV profiled to produce. the optical prism roof. is shown in Figures-9 to l1 inclusive and Figure 13. In Athis mechanism,- the work-carrier com- `prises a. disc-wheel 84, provided with a series of work-receiving Seatsarranged in spaced rela- .tion along the periphery of said wheel, each seat embodying cooperating-fixed work-engaging sury faces 85 and 88. 'lhe surface 85 is adapted to receive the base-of a prism and, as shown, is

` slightly shorter than the base of a prism superimposed thereon, and of approximately the same width, while the surface 88 is disposed at an angle to the surface 85, at onegend thereof, to

conform to the angularity of an end face of such A prism, the length ofthe surface 88l being less of the prism will project beyond the outer edge of said surface, when the prism base is in registwo surfaces are integral, they may be otherwise Athe intermediate portion formity with the lesser number of levers and the' disposition of their fulcrum points relatively to the cam surface.

Similarly to the cams 34 and 89,the cam surface 98 is effective to progressivelyactuate the levers 88 in opposition to their springs 9| and to progressively control theirspring-induced movement to prism clamping position, in the manner previously set forth, the prisms being insertable with its base in registration with the surface 85 and one end face associated with the angularly disposed surface 86. Thus. as -the opposite end face of the prism is engaged by the portion 98 .of the lever 88, the prism is urged into positive contact with the twol xed seat-defining surfaces an'd locked against relative movement by the-clamping action of the lever, the apex'of the prism projecting beyond the outer edge of surface 86 and the terminus of the curved prism- A engaging portion 98 of said 1ever,;as clearly shown than the height of the prism, so that the apex tration withazhe surface 85. While, as shown, the

formed, both of -them being, preferably, faced Y with fibrous or other suitable material, indicated at 85a and8ia, to protect the faces of the prism .in contact therewith against damage.'

Mounted for rocking movement on a screw '81,

. adjacent each seat, in proximityV to the end of the surface 85 remote from the surface 86,-is a lever 8l, the inner end of which is bifurcated to provide a mounting for a cam roll'er 89, while the outer endof` said lever is'shaped in a lreverse curvature to form a prism-engaging surface 90, v which. similarly, to the fixed surfaces 85 and 86,

is provided with aprtective material, as indicated at 9la.- An expansion spring 9|, interposed between the seat 9 2 on said .lever 88, adjacent the inner end thereof and the seat 93 formed on the inner sideof the surface 85, normallyv in Figure 9. Inner and outer prism guides, indicated at 99 and |98, cooperate in aligning the prismin its seat, as itpasses between them, as

set forth in the detailed descriptions ofthe mechanism of Figures 1 and 2.

l As the work-carrier'revolves, the prisms of the contour shown in view |2a of Figure 12, are suc-"- cessively introduced to'a pair of grinding elements g, which coact to simultaneously bevel the 'side faces of the prism passing therebetween, ad-

jacent its apex, as shown in view |21, the prism then progressing to a single grinding wheel, indicated at h, which reduces ing edgeio a fiat surface, as illustrated in view ,the sharp 'apex-delin- I2c, and finally to another pair of coacting grinding elements i, winch further reduce `the bevelled surfaces produced in the first step 'of the operation, to attain the ultimate roof profile of the optical prism, as in view lj2d of said Figure 12.

The grinding elements g, h and i are mounted below the work-carrier, in the path of travel of the projecting portions ofthe prisms clamped in the work-receiving seats, similarly to the grinding elements of the` mechanisms previously described,

thepaired grinding wheels m and In, wherebyv theilrst step of the operation is performed being xed to the shaft lOl-With a suitable spacer IM interposed therebetween, as shown in Figure gli.

. The' mated grinding wheels for performing the functions to urge the prism-engaging end of the third and fin-al step of the operation, indicated at i in Figure 9, correspond to the wheels Ill and |02, the wheels 0f both sets having opposed bevelled surfaces Illa and "2a, between which the protruding portions of the prisms pass in the initial bevelling step and in the final reducingv step of this operation. 'I'he single grinding wheel |85, which flmctions'in the intermediate step of the roof-forming operation, indicated at h in Figure9, to reduce the apex to a flat surface, is rotatable with the shaft |06 and otherwise corresponds to the vgrinding wheel 12,` employed inthe end-reducing and pronling mechanism.

The mountings for the work-carrier shafts l1,

65 and 95, of the respective mechanisms, in the machine frame, correspond one with the other, as

, do the driving means for these shafts: also the shaft of each of the several grinding elements, whether of the single or double type, is vertically adjustable, as heretofore stated, so that the grinding element carried thereby may be raised toward the work-carrier, with which it is associated, to compensate for wear in the abrading surface thereof. Therefore, the description of the mounting of the shaft 95 of Figure l3, together with its the grinding elements, as a coolant for the move,

driving means, will be understood to apply also to shafts |1 and 65 of the side-forming and endreducing and profiling mechanisms, while the description of the assembly of the grinding element being associated with the outer bearing. |00, as

shown. Keyed to said shaft 05, between the bearings |01 and |00..is a\worm gear lll, in mesh with a worm ||2 fixed to the cross shaft `I I3, the

shaft H6 or from ratus. f

A trough |26 is secured to the side of the apparatus and serves to contain the lubricant, preferably water, within which the grinding elements perform their functions, the level of such lubricant being such as to provide for 'the continuous lubrication of the-grinding elements operable in the respective stages as the work is continuously moved in its path; the aforesaid liquid serving, in addition to its lubricating function in relation to ing members of the mechanism and the prisms beig treated.

While we have described the embodiment of'our invention as herein shown, in more or lessdetail,

it will be manifest thatthe various changes may be effected in the structure of the different components, to meet specific requirements of production and use. For instance, the 'work-carriers' functioning in the different operations mayl vary in design from those shown and described and the method of mounting the grinding elements and providing for their adjustment relatively to the work clamped to the work-carrier may diifer,'a1l of these and such other changes of structural 'details ,as may be essential to the practical application of our invention, coming within the spirit and scope of this disclosure, which .isbro'adly directed to the attainment of the objectives hereinbefore set forth by the method described and 'apparatus for rendering such method effective;

latter shaft carrying a worm gear meshing with a worm IIS on the drive shaft H0; suitably mounted in the frame of the apparatus and driven in any appropriate manner, the gearingratio bev ing such that the shaft will revolve at slow speed, as for example, eight or ten revolutionsfper minute. Obviously, the shafts of the several mechanisms may be otherwise mounted and other meansthan described may be utilized for effecting rotative movement of the respective workcarriers. However, a worm gear drive of the type shown gives the desired reduction andinsures a continuous steady rotative movement of the work-carrier, possible back-lash that might occur with other types of gear trains being elimi- Dated. '/w' I j For'mounting the grinding element shaft assembly, a bearing ||1 extends apparatus frame below and parallel to bearings' |`01and |00, the inner face of this bearing being complemental to the periphery of the eccentric sleeve ||0 insertable therein, in which the grinding element shaft |00 is concentrically mounted, in the roller bearings ||0 andl20, adjacent the respective ends of said sleeve, in association with theu'sual retainers i2 I ,and packing rings |22, the eccentric sleeve being positively! locked in the bearing |1 by the locking rings |20 and |20 in engagement with each end thereof. will be evident, the shaft |00 and the grinding wheel |05 keyed ythereto may be raised in .the vertical plane of the work-carrier by manipulatingl the aforesaid locking rings to permit of the rotation of the'eccentric sleeve within the bearing ||1 to reverse'its position from that in which it is shown in Figure 13, the locking rings being thenfunctioned to positively maintain it in such adjusted y position.

the shaft |00 has keyed thereto whereby the shaft may be of a belt traversing At its outer end a grooved pulley |20, driven through the medium We claim:

1. A work-carrier for -apparatus for grinding optical prisms, having circumferentially spaced fixed prism-receiving seats, each seat embodying surfaces conformed to receive a prism ap plied thereto only in a pre-arranged position, to permit portions of the prism to project beyond the seat, yieldable means` associated with each seat adapted to frictionally engage a surface of the prism to retain it in position within said seat, a' lever pivotally connected to said carrier adjacent each of said seats formed for engaging prism surface, spring means for urging said lever into engagement with the opposed prism surface to exert clamping effort thereon counter to said friction means, for locking the prism within the seat, and ya roller carried by said lever, whereby 'said lever may be actuated in opposition to said spring to release the work for removal from its seat.V

2. An apparatus for grinding optical prisrngs,

ircluding a rotatable prism-carrier provided posite at surfaces of a prism disposed thereon and defining the sole position, in which a'prism may be'located on a seat' to dispose portions thereof to project beyond the area of said seat, clamping means associated witheach of said seats for locking the prism therein, means for -rotating said carrier in' a vertical plane, a se.

ries of grinding elements mounted for rotation in the plane of said' work-carrier,` in pe*- ripherally spaced relation to` each other in the path of travel of the projecting portions of the prisms seated on said carrier, whereby the rotation of said carrier will simultaneously .expose the projecting portions of aplurality of prisms to the action of said elements, to progressively reduce the projecting portions of consecutive prisms in a predetermined amount, means iixed with relation to said the same, from a cooperatingpulley on the drive carrier embodying a cam surface conformed for some other point of the appaengagement by said clamping means to progressively urge said clamping means into clamping engagementV `with successive, prisms, following their location in said seats and on completion of said reduction operation to sequentially operate said clamping means to. release the prisms for removal from their respective seats, andv arranged position, the widthv of the seat beingv less than the width ofthepprism, whereby the sides of the latter will project beyond the seat, means for clamping the prisms in their respective seats, operative sequentially in a predetermined part of a cycle of said carrier, a 'series of sets of paired grinding elements rotatable on axes parallel to the axis of rotation of said carrier, the respective sets of elements being with the effective surfaces of the elements of 4peripherally spaced relatively to each other lastanti ing element and two sets of paired grinding elements, the elements of each of the two latter sets vhaving their effective surfaces laterally spaced, all of said elements being disposed in the path of travel of the projecting apex of the prisms seated on said carrier, the rotativemovement of the carrier successively introducing the prisms to a set of paired elements, then to the single element and nally to the remaining set of paired. elements, the rst operation simultaneously bevelling the cornersof the apex, the sec- A ond reducing the height of the prism .and the each pair disposedin the path of 'travel of lthe side portions of the prisms projecting laterally of the carrier seats, whereby i the rotative movement of the carrier will sequentially introduce the prismsy to the successive sets of grinding elements for progressively reducing, the projecting side portions of 'thel prisms to a predetermined degree, the opposite sides of each prism being simultaneously rev duced in the same amount, by the paired grinding elements ofeach set lof the series.

'4. An apparatus for grinding optical prisms,

'including a rotatable work-carrier provided with relatively annularly spaced seats, each being adapted to receive a prism, disposable therewill protrude beyond said seat, means for clamping the' prisms in their respective seats `operable sequentially in a-predeterminedrotative movement of the carrier,.a series of grinding elements rotatable on axes'parallel to theaxis of rotation of said carrier, said series including single sets having their eiective surfaces laterally -on.in Ia position whereby one end of the prism l taneous reduction of the sides of each prism, as

spaced and of a similar contour, all of said elements being disposed in the path of travel of the projecting end portions of the prisms seated on said carrier, whereby the rotative movement of said' carrier will successively introduce the third reducing the bevelled surfaces produced in the first operation.

6. A method ofprocessing a molded glass triangular prism in its conversion into an optical prism in a series of co-related automatically per formed operations, which consists in simultaneously subjecting'both sides of the prism to progressive reduction in the desired amount in a single continuing operation, thenreducing one end of the prism and subjecting it to contour .shaping in successive stages, in which opposite and connecting surfaces are simultaneously and progressively reduced to obtainlthe final end contour, in a second continuing. operation, simi- -`larly reducing and profiling-the other end of the prism in a corresponding second step of the end grinding operation and then successively bevelling the' corners of the prism apex, reducing the apex to, form the optical prism roof and reclucing the bevelled comer-forming surfaces to attain the'ultimateroof prole in the final continuing operation of the' series. f f

'7. A method of converting a plurality of molded glass triangular prisms of corresponding dimensions into identical optical prisms, in' a' series of' co-related continuing mechanical operations, ,which consists in successively introducing the prisms in a.uniform arrangement to grinding elementsfor effecting the. simulthey are presented to such elements, in the rst of such continuing operations, then successively introducing the same prisms in a'- second vand 'different uniform arrangement to othergrinding elements for reducing one end of the prism and jecting them to reducing and profiling, grinding in a'. second continuing phase of the end- `-forming operation and thenvsuccessively introrespective prisms'to said single grinding element t;

and in sequence to each pair of elements, said single element acting `to reduce the end portion, the paired grinding elements` acting upon the reduced end to progressively change ,the contour thereof.

5. An apparatus for grinding optical prisms,

including a rotatable work-carrier provided with relatively annularly spaced seats, each being formed for the reception of a prism centered thereon to project the apex of the prism beyond the seat, the base of the prism being disposed toward the axis of the carrier, means for clampmeans becoming sequentially effective during a predetermined degree of rotative movement of said carrier, a series of grinding elements rotating the prisms in their respective seats'. said `ducing the prisms in a third and furtheruniiorm arrangement to additional grinding elements for bevelling the corners 'of the apex of each port a plurality of glass prismsthrough a zone.

for reduction byA contact with grinding elements, in a continuing .cycle of movement, said workcarrier having fixed surfacesrelatively disposed for locating the prisms in contact therewith in a predetermined uniformposition. spring-actu-- atedvwork-engaging. means adapted to ,coopern ate with said fixed surfaces, in a clamping action, to hold the prisms immovable'relatively to said work-carrier, during their passage through said zone, and xed -means associatedv with said work-carrier, comprising a cam element having a continuous curved peripheral surface, then radius of which varies gradually without 'abrupt change between ,a minimum and a maximum,

` ally increasing composition to the springs thereof from work-clampingt work-releasing position, the engagement of the work-engaging means bythe peripheral cam surface in opposition to the springs lof, the former being proi gressively decreased and the 'former being displaced from work-releasing to work-clamping position during a succeeding part of the cycle of movement of said work carrier.

9. An apparatus for grinding optical prisms, including a rotatable work-carrier provided with circumferentially spaced fixed prism seats, each embodying surfaces conformed to mate with the base andV one end wall of a prism, the width of the seat being less thanthewidth of the prism, whereby the sides of the latter will project outwardly of the seat,- mean's forclamping the prisms in their respective 'seat, each of said clamping means embodyinga portion conformed to engage the end wall of the prism opposite to that in fixed engagement with the seat surface, a fixed cam engageable by said clamping means for actuating said clamping means in'.

sequence to clamp each prism in its seat, during a predetermined part of the cycle of said carrier,l in axprogressively increasing pressure-exerting movement of'the portion of said clampingn means .engageable with the opposed prism end, a series of relatively' spaced sets of paired vgrinding elements rotatable onaxes parallel to the axis of rotation of said carrier disposed for the passage of the prisms therebetween with their opposite projecting sides abradingly engaged by each pair ofV elements, whereby in a continuing cycle of movement of said carrier consecutive will be successively introduced to each set of grinding elements for progressively reducing the projecting sides oi each. prism to produce an ultimate pris'mof a predetermined width, the spacing of said sts of grinding elements relative to the circumferential spacing of the prism seats providing'for the. simultaneous reduction of the sides of a plurality of prisms in traversing engagement with the eifect'ive surfaces of the spaced sets of grinding elements.

10. An apparatus for grinding optical prisms,

including a rotatable'work-carrier provided with circumferentially spaced fixed prism seats, each seat embodying surfaces conformed to mate with 'prisms one end wall and a portion of the opposite end wall of a prism in engagement with the apex -thereof, to dispose one end of the prism beyond the periphery of said work-carrier, means for clamping the prisms each of saidclamping means including a portion conformed to' engage .the base. of theseated prism, a fixed cam surface engageable by said clamping means for actuating said clamping means in sequenceto clamp each prism in its seat, during a predetermined part of the cycle of said carrier, in a progressively increasing pressure-exerting movement of the portion of engageable `with the opposed prism base, a series of relatively vspaced 'grinding elements, certain of said elements being paired, an or said` elements being rotatable on axes parall'l to the axis of rotation of saidwork-carrier and being disposed relative ,to the in their respective seats,

successively introducedv to said grinding elements for progressively reducing the projectl ing end of each prism to produce an ultimate predetermined end contour, the spacing of said grinding elements relative to the circumferential spacing of the prism seats permitting of the simultaneous reduction of the ends ofa plurality of prisms in traversing engagement with the effective surfaces of the relatively spaced grinding elements.

11. An apparatusl for grinding optical prisms. including a `rotatable work-carrier provided with circumferentially spaced prism seats,` each embodying surfaces conformed to mate with the base of a prism and a portion of one end wall thereof and cooperate to locate the apex of a prism entered in said seat outwardly of the periphery ofl said work-carrier, means for clamping the prisms in their respective seats. each of. said clamping means including a portion shaped to engage with a major portion of the end wall of the prism opposite to the end wall, thereof engaged with said seat surface, a xed cam having a surface engageable by said clamping means for actuating said clamping means in sequence to 1clamp each prism in its seat, during a predetermined part ofV the vcycle of said carrier, in a progressively increasing pressure-exerting movement of the prism wallengaging portion of said\ clamping means with the opposed prism wall, a series vof relatively spaced grinding elements' mounted for rotation `relative to the circumferential spacing of the prism'seats permitting of the simultaneous reduction of' the apex-forming surfaces of a. plurality of prisms in traversing engagement with the effective surfaces of the relatively spaced grinding elements. f

12. An apparatus for grinding optical prisms, comprising a rotatable work-carrier adapted to transport in a continuous cycle of movement a plurality of optical prisms from a first zone, in which unground prisms are fed to the workcarrier, through a zone for reduction by contact with grinding elements and back to the first zone for removal of the ground prisms, said work-carrier having fixed surfaces peripheral] disposed for mounting the prisms in predetermined spaced positions, spring-actuated workengaging means associated with said work-carrier for movement therewith and adapted, in a clamping action, to cooperate with said fixed surfaces, for maintaining the prisms immovable during their passage through said reduction zone, and a xed cam element associated with said work-carrier having acontinuous curved" peripheral surface the radius of which varies progressively and without abrupt change. from 2,355,551 va. minimum in correspondence to said reduction zone to a maximum in correspondence tosaid first zone, said work-engaging means being engageable by said peripheral cam surface duringthe travel o1' these former from said reduction zone to said ilrst zone, to gradually displace said work-engaging means in progressively increasing oppositionto the springs thereof from workthe springs of the former being progressively decreased during the travel of said work-engaging means from the ilrst zone to the reduction zone,

clamping to work-releasing position, the displacing engagement of the work-engaging means by the peripheral cam surface in opposition to- 

